The disclosure relates generally to power systems, and more particularly, to reducing operational costs for gas turbine system and/or power plants while maintaining a desired load or power output.
Power systems typically include a variety of different turbomachines and/or systems that are used to generate operational load and/or power output. Two conventional power systems used to generate operational loads include gas turbine systems and combined cycle power plants, which typically include a gas turbine system(s). Conventional combined cycle power plants employ one or multiple gas turbine system(s) operatively coupled to one or multiple steam turbine system(s). The gas turbine system includes a compressor coupled to a gas turbine. The gas turbine is usually coupled to and drives an external component, such as a generator, for producing a load or power output. The steam turbine system includes a high pressure (HP) turbine portion operatively coupled to an intermediate pressure (IP) turbine portion that, in turn, is coupled to a low pressure (LP) turbine. Similar to the gas turbine of the gas turbine system, the HP, IP and LP turbines are employed to drive an external component (e.g., generator). In a typical combined cycle power plant, exhaust gas from the gas turbine is passed to a heat recovery steam generator (HRSG), which may be used to reheat and provide steam to the various turbines of the steam turbine system for enhanced efficiency of the system and/or power plant. Downstream of the HRSG the exhaust gas is released to the atmosphere through a stack.
Various operational parameters and operational concepts (e.g. bypass, speed, throttle and the like) influence the operation of conventional power systems (e.g., gas turbine systems, combined cycle power plants). For example, the operational parameters and/or characteristics (e.g., maximum hot gas temperature, maximum rotational shaft speed, maximum mass flow for steam, and so on) of the power system and its various components (e.g., compressor, gas turbine, HP/IP/LP turbines) may determine the operational life and/or maximum operational load and/or power output that conventional power systems are capable of producing. As such, the conventional operation conditions and/or operational load for conventional power systems are typically predetermined based on the operational parameters, concepts and/or characteristics of power systems, and its components, to improve the operational life, power output and efficiency of the power systems. In some conventional examples, conventional power systems may even include various stages or fixed operational lines (e.g., low, intermediate, high), where each line may produce or generate different operational loads based on changes to the operation conditions of the power system and its various components. For example, the high operational line may generate a larger operational load than the intermediate or low operational line by increasing the turbine outlet temperature in the power systems.
However, these conventional power systems (e.g., gas turbine systems, combined cycle power plants) and/or operational conditions and/or control of the power systems do not take into consideration costs associated with operating the power system. For example, determining the operation conditions and more important control settings of conventional power systems typically do not include considering and/or analyzing fuel costs for a gas turbine system and/or the maintenance costs of components of the power systems. As such, in some examples, changes to the operation concept of conventional power systems, while generating a larger or the same operational load, may significantly increase costs associated with the operation of the power plant.